Round cutting inserts may often manage a number of profiling operations from fine machining to rough machining. Usually, the round cutting inserts generate a fine surface also in connection with high feed rates because the round edge functions as a wiper.
Contour/profile-turning machining operations present a unique problem due to continuously changing cutting conditions, and the associated wide variations in chip flow and the consequent chip form and surface finish issues due to geometric variations along the length of cut. The chip control may easily become deficient, especially in connection with small cutting depths when relatively wide and thin chips are formed that could be hard to break. As a result, long curled chips are formed that at worst may entangle around the insert holder and scratch the generated surface and possibly cause insert breakdown.
Unfortunately, in many contour/profile-turning cases, a round insert is the only option due to the exclusive shape of the workpiece. Unlike other insert styles, (e.g. C-shaped: 80 degree nose angle, or D-shaped: 55 degree nose angle), the round insert allows the use of any part of the cutting edge (i.e. 360 degree nose angle) to engage the workpiece during the machining process.
Currently, conventional round cutting inserts have the same chipbreaker feature along the entire 360 degree cutting edge. However, due to an insufficient understanding of the contour/profile-turning process and the distinctive geometry feature of the round insert, the currently available round insert chipbreaker feature is not efficiently designed to properly control and break chips. As a result, the conventional round insert is designed for only two types of machining operations: 1) a roughing process with a large depth of cut and high feed rates, and 2) a finishing process with a small depth of cut and slow feed rates.
Thus, there is a need to provide a single round insert with improved chip control that provides the capability to perform both a roughing machining operation with large depths of cut at any desired feed rate, and a finishing machining operation with small depths of cut at any desired feed rate.